Magnite director plans sale of 10,363 shares

Available on EDGAR 09/14/2026 - 05:51 PM EDT Accepted by SEC EDGAR 09/14/2026 - 05:50 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) director Robert Spillane has filed a Rule 144 notice for a potential sale of common stock. The notice covers 10,363 shares of Magnite common stock to be sold through Morgan Stanley Smith Barney LLC following a stock option exercise for cash, with an indicated aggregate market value of $246,241.46. The shares are listed on NASDAQ and the intended sale date stated is September 14, 2026.

Key Figures

Shares covered by Rule 144 notice: 10,363 shares Aggregate market value: $246,241.46 Intended sale date: September 14, 2026

3 metrics

Shares covered by Rule 144 notice 10,363 shares Common stock to be sold following stock option exercise

Aggregate market value $246,241.46 Indicated value for the 10,363 shares of Magnite common stock

Intended sale date September 14, 2026 Date listed for sale of shares under Rule 144

Key Terms

Rule 144, Stock Option Exercise, aggregate market value

3 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Stock Option Exercise financial

"Common | 09/14/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

aggregate market value financial

"Common | Morgan Stanley Smith Barney LLC ... | 10363 | 246241.46"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does the Form 144 filing disclose for MAGNITE, INC. (MGNI)?

The filing discloses that director Robert Spillane has filed a Rule 144 notice covering a potential sale of 10,363 shares of Magnite common stock following a cash stock option exercise, with an indicated aggregate market value of $246,241.46.

How many MGNI shares are covered by Robert Spillane’s Rule 144 notice?

The notice covers 10,363 shares of Magnite, Inc. common stock, as stated in the securities information and securities-to-be-sold sections of the Form 144.

What is the indicated aggregate market value of the MAGNITE (MGNI) shares in this Form 144?

The Form 144 lists an indicated aggregate market value of $246,241.46 for the 10,363 shares of Magnite common stock covered by the notice.

How will the MGNI shares related to this Form 144 be obtained and sold?

The shares are tied to a stock option exercise for cash from the issuer, with the Rule 144 notice stating that 10,363 shares of common stock are to be sold through Morgan Stanley Smith Barney LLC.

When is the intended sale date for the MGNI shares in this Form 144?

The Form 144 lists an intended sale date of September 14, 2026 for the 10,363 shares of Magnite common stock covered by the notice.

On which market are the MGNI shares in this Form 144 listed?

The shares of Magnite, Inc. common stock referenced in the Form 144 are listed on NASDAQ, as indicated in the securities information section.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001603808
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	MAGNITE, INC.
SEC File Number	001-36384
Address of Issuer	1250 Broadway, 9th Floor New York, NEW YORK 10001
Phone	(212) 243-2769
Name of Person for Whose Account the Securities are To Be Sold	ROBERT SPILLANE
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	10363	246241.46	143424157	09/14/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	09/14/2026	Stock Option Exercise	Issuer			10363	09/14/2026	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	09/14/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Robert F Spillane
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)